The XM577A4 Stretch has an interior volume of 502 cubic feet (an increase of 108 cubic feet) and a payload capacity of over 5000 pounds, making it equivalent in capacity to the S-280 tactical shelter. The XM577A4 Stretch Armored Tactical Command and Control System is a prototype Stretch version of the M577A3 Armored Command Post. By using the RISE power package, the vehicle incorporates a sixth road wheel and longer hull to provide more interior space and increased payload capacity.The XM577A4 Stretch is capable of carrying bolt-on armor as well as crew compartment spall liners for additional side and top attack protection. The XM577A4 stretch was developed by United Defense, L.P. as an Independent Research and Development program. This vehicle is currently being considered as a platform for Hazardous Material Operational Roles.